Of course, parenting comes first and foremost and the parents are responsible for the accident. Your responsibility, as a parent, doesn't end with just giving birth to your children, but extends to raising them and guiding them every step of the way. If that is not the case, then what is the difference between you and a donkey. You, as a parent, should give freedom to the children, but at the same time you should also tell them what is right and wrong, what are the dangers involved in engaging in a particular conduct, etc. You, as a parent, have life experiences and has a lot more knowledge, while the children do not, and as a consequence, they are prone to make mistakes, such as this accident, or even commit crimes.
Society has come to a point where we are right now, because people do not value relationships even with their own family members the same way and to the same extent as they used to before. People have no value for the other person's life anymore. Not everyone, but I see a lot of them with that attitude and mindset.